Commentary: Reasoning Versus Post-truth

Nicolaus Copernicus’s heliocentric model of the universe was reasoned from evidence but conflicted with popular beliefs of the day.

The Oxford Dictionaries word of the year for 2016 was post-truth, defined as “denoting circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief.” Science is not immune to appeals to emotion and belief rather than fact.

To help us challenge the drift toward post-truth, the history of science reminds us of the qualities that support all the practices of science, including evidence-based reasoning.

The evolution of evidence-based reasoning
Empirical evidence and reasoning have not always been at the heart of the scientific enterprise. Evidence-based reasoning evolved in response to beliefs that were increasingly untenable to early natural philosophers. In the early 1600s, the first scientific academies were established in part to uphold the primacy of experiment in questions about the natural world. Such a stance was counter to scholasticism, the dominant medieval method of learning “rooted in Aristotle and endorsed by the Church, [which] involved certain beliefs about the celestial realm … as well as the terrestrial realm of Earth” (Carlin 2009, p. 5).

Synthesizing Christianity and Aristotelian thought, scholasticism viewed the universe as simultaneously religious and physical. The scholastic reaction to the heliocentrism put forth in the 1543 publication of De revolutionibus orbium coelestium is entirely understandable: Copernicus challenged not just a “scientific” model of the universe but also a view of man’s place in creation.

The difficulty that philosopher and scientist Francis Bacon had with deductive scholasticism was that it was static, not permitting new knowledge to develop. By introducing and promoting induction as a method for studying nature, Bacon profoundly influenced the course of scientific inquiry: “Under the leadership of Francis Bacon, most of the empiricists would come to believe that a natural philosophy rooted in experimentation, as opposed to the purely theoretical … method employed by scholastics, was crucial to understanding nature’s ways” (Carlin 2009, p. 11, emphasis in original).

Empiricism challenged scholasticism by relying on rigorous observation, experience, and, increasingly, the belief that “all natural change can be explained in terms of the mathematical properties of matter in accordance with laws of nature” (Carlin 2009, p. 11). One of the centers of this intellectual struggle was Florence.

The Accademia del Cimento
Artists and natural philosophers, supported by the House of Medici, helped make Florence, capital of the Grand Duchy of Tuscany, a cultural, political, and economic powerhouse. After Galileo died in 1642, both Grand Duke Ferdinano II and his brother Prince (later Cardinal) Leopoldo recognized the political value of continuing to support Galileo’s experimental practices.

This led to Leopoldo’s creation of the scientific Accademia del Cimento in 1657. In 1664, the Accademician Francesco Redi recorded that Leopoldo was interested in science “not for vain or idle diversion, but rather to find in things the naked, pure, genuine truth” (Feingold 2009, p. 231). Leopoldo’s commitment to experimentation was captured in the Accademia’s motto: Provando e riprovando (Test and Test Again).

The Accademia was charged with the standardization of measures and scientific methods and the development of standard scientific instrumentation. The main experimental interests centered on thermometry, chemistry, medicine, and pneumatics. Experimental work was carried out in Florence, Livorno, Pisa, and Pistoia.

Leading Accademicians included the physicist and mathematician Viviani; the physiologist, physicist, and mathematician Borelli; and the physician, biologist, and poet Francesco Redi, whose seminal 1668 work, Esperienze Intorno alla Generazione degl’Insetti (Experiments on the Generation of Insects), marked the beginning of the end of abiogenesis.

Experimentation and evidence
The Accademicians regarded experimentation as central to the practice of science, directly in contrast to both Aristotle and the Church. The preface to the Accademia’s famous Saggi di naturali esperienze (Essays on Natural Experiments) (the “Saggi”), published in 1667, argued that experimentation was central to understanding the physical world:

… there is nothing better to turn to than our faith in experiment. As one may take a heap of loose and unset jewels and seek to put them back one after another into their setting, so experiment, fitting effects to causes and causes to effects… performs enough so that by trial and error it sometimes succeeds in hitting the target.

The preface was also clear on the need to reason from evidence, recognizing that it was necessary at times to return to prior experimentation and reasoning:

Besides trying new experiments, it is not less useful to search among those already made, in case any might be found that might in any way have counterfeited the face of truth.

The Saggi emphasized the importance of mathematical reasoning in descriptions of experimental work. In doing so, the Accademicians worked to remove any reference to philosophy or mythological cosmology from experimental science and so establish the authority of experimentation in questions about the natural world. This was an overt challenge to the prevailing scholastic view of the natural world.

To reason from evidence is not simple, as it opens the evidence to speculation and argumentation. The Accademicians often struggled to reconcile their interpretations of the experimental data. Leopoldo, the Accademia’s patron, actively engaged in these scientific conversations, challenging, and being challenged by, the other Accademicians to the extent that some “thought they could speak freely” with him (Feingold 2009, p. 232). A particular point of contention within the Accademia was the range of views about the relationship between experimentation and the still powerful approach of Aristotle. These competing views stimulated “sharp confrontation, often resorting to insults” among the Accademicians (Beretta 2002, p. 12).

The authority of reason
Leopoldo ordered that individual contributions not be credited in the Saggi so that readers would be convinced by the evidence presented rather than the reputation of the author. Also, the Accademicians desired to “underline the impersonal nature of the scientific enterprise” (Beretta 2000, p. 142). In asserting the primacy of the experiment and reason over the hegemony of scholasticism, the publication of the Saggi was a landmark in the history of science.

Understanding modern science
The work of the Accademia set out the need for replicable tests, the control of variables, and the standardization of measurement and instrumentation. It also demonstrated that modern science is more than just knowledge; science is a human endeavor based on curiosity about the natural world, observation, argument, creativity, and reason. These qualities are found in the Next Generation Science Standards (NGSS Lead States 2013). As science teachers, we must model, teach, and practice these qualities if we are to engage our students with the need for evidence and reasoned argument.

The Accademicians struggled to establish the ascendancy of evidence and argument over reputation. While “sharp confrontation, often resorting to insults” may be a bit harsh for our classrooms, scientific discourse requires an environment in which ideas can be put forward, challenged, refined, and challenged further. This practice also includes a willingness to return to experiment and evidence to develop explanations that more closely reflect our current understandings. Such an environment must be crafted by those in authority within the classroom and not left to chance.

Leopoldo promoted and funded the Accademia, and as a powerful Medici, could have demanded deference. That his scientific reasoning was open to challenge serves as an important example. As educators, our challenge is to use our authority in the classroom to engage, alongside our students and as learners ourselves, with all of the practices of science, and thus build trust in those practices.

Post-truth relies on the distrust of both the sources and value of information. This loss of trust in institutions and academic disciplines—including science—along with the wide availability of misinformation that conforms to what people want to hear, diminishes expertise and learning. Drawing from history, we can give students the tools and attitudes needed to challenge those who would devalue reason so that reasoned decision-making can triumph. Just as the Accademicians challenged scholasticism and eventually prevailed, so must we challenge the very idea of post-truth.

Wayne Melville ( is professor of science education and assistant dean at Lakehead University in Thunder Bay, Ontario.

Applying Knowledge in Context:
National Research Council (NRC). 2015. Science teachers’ learning: Enhancing opportunities, creating supportive contexts. Washington, DC: National Academies Press.
Nature of Science:
Scientific Inquiry:

Beretta, M. 2000. At the source of western science: The organization of experimentalism at the Accademia del Cimento (1657–1667). Notes and Records of the Royal Society of London
54 (2): 131–151.
Beretta, M. 2002. Court scientists: The art of experimentation in the Galilean Accademia del Cimento (1657–1667). Institute and Museum of the History of Science, Florence.
Carlin, L. 2009. The empiricists: A guide for the perplexed. London: Continuum.
Feingold, M. 2009. The Accademia del Cimento and the Royal Society. In The Accademia del Cimento and Its European Context, ed. M. Beretta, A. Clericuzio, and L.M. Principe, 229–242. Sagamore Beach, MA: Watson Publishing International.
NGSS Lead States. 2013. Next Generation Science Standards: For states, by states. Washington, DC: National Academies Press.

Editor’s Note

This article was originally published in the September issue of The 
Science Teacher
 journal from the National Science Teachers Association (NSTA).

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